Cyclical Program With 3 Setpoints And 3 Steps; Program With Hbb (Hold Back Band) Function - gefran 850 Installation And Instruction Manual

Configuration of STEP2

5.13.5.4. Cyclical program with 3 setpoints and 3 steps

temforature
SP07
SP05
SP06
Initial
tr5 tp5 tr6
Step 5 Step 6
CICLE 1

5.13.5.5. Program with HBB (hold back band) function

temforature
SP
T
i
tw1 tr tp1
t
off
time
tp6 tr7 tp7 tr5 tp5
Step 7 Step 5
CICLE 2
HBB
Restart program
Power tw = waiting time
OFF
tr = ramp time
tp = formanence time
tp = tp1 + tp2
time
tw2 tp2
t
on
80209C_MHW_850-1650-1850_01-2020_ENG_pag. 214
5.13.6. Fast simulation of program
You can easily check a selected program by launching it
in fast simulation mode. Enable it by setting the parameter
LIMIT = On on the PR.OPT submenu.
The program will run with ramp time limited to 20 seconds
and with hold time limited to 10 seconds. If the set values are
smaller they are used. In this way the maximum duration of
a step is 30 seconds.
During functioning in fast simulation, the HBB alarm is
inhibited and the control output assumes the FAULT value
on the PID submenu.
All other enabled functions (restart, start/stop, reset, manual/
automatic, end cycle or continuous cycle, event outputs,
consent from digital inputs, second channel setpoint, etc.)
are active.
5.13.7. Controlling the program from the
keypad
In the absence of enablings from digital inputs , the program
is controlled when programmer state is displayed using the
, keys, with the following modes:
• pressed with program stopped = START;
• pressed with program running = STOP;
• + pressed for 2 seconds = RESET
(condition maintained with key pressed);
5.13.8. Programmer Reset mode
By setting RST.SP = ON provides that with active reset com-
mand the setpoint assumes the value of process variable PV
and power is forced to zero.
Setting RST.SP = OFF maintains the active setpoint (prior to
reset) and power control.
This function is valid in case of reset from digital inputs or
enabled keys, as well as in case of reset following a program
change (possible only in STOP) or STOP/START switching at
end of program.
5.13.9. Restart with step search
If configured, in case of restart the programmer can try to
restart nor from the first program step but from the point of
the program that corresponds, or is closest to, the value of
the active process variable PV.
This function mode is called "restart with step search."
At start, if Strt = RSCH was set on the PR.OPT submenu,
the program searches for the setpoint with value equal to
variable PV.
The search is conducted by shifting the current time forward
or back and skipping phases or steps.
The following diagram shows a typical 5-step program pro-
file and explains how restart with step search works.